High-power-density large-capacity dry-type water-cooling medium-frequency transformer

Abstract

The invention belongs to the technical field of dry-type transformers, and particularly relates to a high-power-density large-capacity dry-type water-cooling medium-frequency transformer. In order to overcome the defects of a water-cooling heat dissipation structure of an existing medium-frequency transformer, the high-power-density and high-capacity dry-type water-cooling medium-frequency transformer comprises an iron core assembly, a winding assembly; the iron core assembly comprises at least two roll iron cores and an iron core water cooling device, the two roll iron cores are distributed in the thickness direction, and each roll iron core comprises an iron core column, an upper iron yoke and a lower iron yoke. The iron core water cooling device comprises an iron core middle water cooling assembly located between the two roll iron cores and iron core yoke part water cooling assemblies located on the outer sides of upper iron yokes and lower iron yokes of the roll iron cores correspondingly. The winding assembly sequentially comprises a low-voltage winding, an insulating cylinder and a high-voltage winding which are concentric from inside to outside, the low-voltage winding comprises a low-voltage coil and a low-voltage water cooling device, and the high-voltage winding comprises a high-voltage coil and a high-voltage water cooling device. The beneficial effects of the invention are that: heat dissipation is good, the overall size is small, and higher power can be transmitted in unit volume.

Description

Technical Field

[0001] The present invention belongs to the technical field of dry-type transformers, and in particular relates to a high-power-density, large-capacity dry-type water-cooled medium-frequency transformer. Background Art

[0002] With the development of smart grids and the increasing number of renewable energy sources connected to the grid, traditional 50Hz power frequency transformers are no longer able to meet the needs of the expanding modern power system. The application of power electronics has brought new levels of power quality, stability, and reliability to power systems. Isolation power electronic transformers are a key component in renewable energy transmission, playing a crucial role in energy transmission and fault isolation. The core component is the medium-frequency transformer.

[0003] Compared to traditional power frequency transformers, medium frequency transformers for new power systems feature larger capacity, higher voltage, and higher frequency. Medium frequency transformers operate at voltages of 20kV and below, in the medium frequency range of 200-1000Hz. They have a capacity of over 1MVA per unit and are generally flame-retardant and explosion-proof dry-type transformers.

[0004] The increase in frequency directly leads to a sharp increase in core losses. Winding losses also multiply due to skin effect, proximity effect, and eddy current effects. However, the transformer's heat dissipation area is limited, and relying solely on thermal radiation and air convection cannot meet the heat dissipation requirements, let alone increase capacity. Improper heat dissipation structure design can lead to long-term transformer overheating, shortening the transformer's service life and even causing combustion and damage, thereby affecting the stable operation of the new energy grid.

[0005] Existing so-called water-cooled medium-frequency transformer solutions only describe the installation of water-cooling plates or water-cooling channels in the middle of the core, low-voltage winding, and high-voltage winding. These typically only mention the application of water cooling and lack true guidance for transformer manufacturing. In reality, the scientific design of a water-cooling structure not only needs to consider sufficient transformer heat dissipation but also ensures that it does not affect the overall insulation safety of the transformer, such as induced withstand voltage and partial discharge, as well as operability and feasibility during manufacturing.

[0006] For example, some existing solutions use one-piece spiral copper tubes or one-piece water-cooling plates, which have two main defects: first, the manufacturing requirements are high, and the water-cooling device is difficult to fit the winding perfectly. Once the size deviation of the semi-finished winding is too large, the one-piece water-cooling device is difficult to place. Once the size deviation of the semi-finished winding is small, there will be a large gap between it and the water-cooling device. Second, this water-cooling device itself forms a form similar to a wire turn, which may cause an increase in local discharge. Once there is an emergency situation where the water quality deteriorates, the transformer loss will increase or even short-circuit and burn out, posing a safety hazard. Summary of the Invention

[0007] In view of the deficiencies of the existing water-cooled heat dissipation structure of intermediate-frequency transformers, the present invention provides a high-power-density and large-capacity dry-type water-cooled intermediate-frequency transformer to meet the heat dissipation requirements. Further, it achieves the goals of being easy to manufacture, having a small partial discharge amount, and good insulation performance.

[0008] To achieve the above object, the present invention adopts the following technical solution: A high-power-density and large-capacity dry-type water-cooled intermediate-frequency transformer, wherein the high-power-density and large-capacity dry-type water-cooled intermediate-frequency transformer includes:

[0009] A core assembly, in a figure-eight shape, having two transverse parts and two vertical parts;

[0010] A winding assembly, with two groups, respectively sleeved outside the two vertical parts of the core assembly;

[0011] Among them, the core assembly includes at least two wound cores and a core water-cooling device. The two wound cores are distributed along the thickness direction. The wound core includes a core column, an upper yoke, and a lower yoke. The core water-cooling device includes a core intermediate water-cooling component located between the two wound cores and core yoke water-cooling components respectively located outside the upper yoke and the lower yoke of the wound core;

[0012] Among them, the winding assembly sequentially includes a concentric low-voltage winding, an insulating cylinder, and a high-voltage winding from the inside to the outside. The low-voltage winding includes a low-voltage coil and a low-voltage water-cooling device. The high-voltage winding includes a high-voltage coil and a high-voltage water-cooling device.

[0013] For the high-power-density and large-capacity dry-type water-cooled intermediate-frequency transformer of the present invention, its core water-cooling device includes a core intermediate water-cooling component located between the two wound cores and core yoke water-cooling components respectively located outside the upper yoke and the lower yoke of the wound core. This layout of the core water-cooling device not only meets the cooling requirements of the iron core, especially the cooling requirements of the upper and lower yoke positions with higher temperature rise, solves the heat dissipation of the iron core, but also enables the cross-sectional area of the core column to be smaller and the overall structure of the transformer to be more compact; the low-voltage winding includes a low-voltage coil and a low-voltage water-cooling device, and the high-voltage winding includes a high-voltage coil and a high-voltage water-cooling device, realizing reliable heat dissipation of the low-voltage coil and the high-voltage coil; the overall volume of the transformer is small, and a higher power can be transmitted per unit volume, that is, it has a high power density.

[0014] As an improvement, the core intermediate water-cooling component includes an independent U-shaped plate and a straight plate, and the U-shaped plate and the straight plate enclose a ring.

[0015] As an improvement, the core yoke water-cooling component includes four water-cooling plates located on both sides of the core assembly in the thickness direction. The core assembly further includes a clamping component, and the clamping component fixedly connects the core yoke water-cooling component, the core intermediate water-cooling component and the two wound cores.

[0016] As an improvement, the wound core is formed by stacking ultra-thin silicon steel sheets, or the wound core is formed by winding amorphous alloy strips or nanocrystalline strips; and / or,

[0017] The plates of the iron core water cooling device are made of aluminum alloy as the base material, and the water flow channels are formed by groove friction welding or buried copper pipes.

[0018] As an improvement, the low-voltage winding also includes glass mesh cloth and high thermal conductivity epoxy resin. The low-pressure glass mesh cloth is located on the inside and outside sides of the low-pressure water cooling device. The low-pressure glass mesh cloth separates the low-pressure water cooling device from the low-voltage coils on the inside and outside sides. The low-voltage coil, low-pressure water cooling device and low-pressure glass mesh cloth are all encapsulated in the high thermal conductivity epoxy resin.

[0019] As an improvement, the water inlet and outlet interfaces of the low-pressure water cooling device are arranged at the lower part of the low-voltage winding; and / or,

[0020] The thickness of the low-voltage glass mesh meets the electric field strength requirement of ≤800V / mm; and / or,

[0021] The low-voltage coil is wound with copper foil with a thickness of ≤1.0mm. When copper foil with a thickness greater than 1mm is required, two copper foils are stacked and insulating paper is placed between the copper foils. Alternatively, the low-voltage coil is wound with multiple Litz wires in a layered flat winding manner, and each Litz wire is insulated with polyimide film or aramid paper.

[0022] As an improvement, the high-voltage coil includes an upper coil and a lower coil that are wound separately, and high-thermal conductivity epoxy resin is filled between the upper coil and the lower coil. The high-pressure water cooling device includes an upper water cooling device at the upper coil and a lower water cooling device at the lower coil that are independent of each other.

[0023] As an improvement, the water inlet and outlet interfaces of the upper water cooling device are located above the upper coil, and the water inlet and outlet interfaces of the lower water cooling device are located below the lower coil; and / or,

[0024] High-pressure glass mesh cloths are provided on both the inner and outer sides of the high-pressure water cooling device to separate the high-pressure water cooling device from the high-voltage coils on both the inner and outer sides. The high-voltage coils, the high-pressure water cooling device, and the high-pressure glass mesh cloths are all encapsulated in a high-thermal-conductivity epoxy resin. The thickness of the high-pressure glass mesh cloth is 1.0-3.0 mm, and the electric field strength is ≤800 V / mm. And / or,

[0025] The high voltage coil is wound with flat copper electromagnetic wire, the thickness of the flat copper wire is ≤2.0mm, and the width of the flat copper wire is ≤6.0mm.

[0026] As an improvement, the low-pressure water cooling device and / or the high-pressure water cooling device includes at least two independent L-shaped structures in a ring shape, the L-shaped structure is formed by bending a pipe, or the L-shaped structure includes two vertically distributed water-cooling plates and an arc-shaped pipe connecting the two water-cooling plates.

[0027] As an improvement, the cooling water channels of the core water cooling device, the low-pressure water cooling device and the high-pressure water cooling device do not share aluminum and copper at the same time; and / or,

[0028] The water inlet and outlet interfaces of the iron core water cooling device, the low-pressure water cooling device and the high-pressure water cooling device have insulating connecting parts.

[0029] The beneficial effects of the high-power density, large-capacity dry-type water-cooled medium-frequency transformer of the present invention are as follows: the iron core water-cooling device includes an iron core middle water-cooling assembly located between the two wound iron cores and an iron core yoke water-cooling assembly located on the outside of the upper iron yoke and the lower iron yoke of the wound iron core respectively. This layout of the iron core water-cooling device not only meets the cooling requirements of the iron core, especially the cooling requirements of the upper and lower iron yoke positions with higher temperature rise, solves the heat dissipation of the iron core, and at the same time makes the cross-sectional area of ​​the iron core column smaller and the overall structure of the transformer more compact; the low-voltage winding includes a low-voltage coil and a low-pressure water-cooling device, and the high-voltage winding includes a high-voltage coil and a high-pressure water-cooling device, thereby realizing reliable heat dissipation of the low-voltage coil and the high-voltage coil; the overall volume of the transformer is small, and higher power can be transmitted per unit volume, that is, it has a high power density. Furthermore, at least one of the upper and lower yokes of the wound core is assembled with the core column, and the water-cooling component in the middle of the core includes a U-shaped plate and a straight plate. The core assembly can be opened to facilitate the assembly between the winding assembly and the core assembly; the high-voltage coil includes an upper coil and a lower coil that are wound separately, so that the interlayer voltage is low, the local discharge is small, the interlayer insulation thickness is reduced, and the upper and lower water outlet settings and insulation safety of the high-pressure water cooling device are convenient, and it is also beneficial to reduce the volume of the high-voltage coil and save costs; the low-pressure water cooling device and the high-pressure water cooling device of the winding assembly both adopt two independent L-shaped structures, which fit the coil better. At the same time, the low-pressure water cooling device and the high-pressure water cooling device do not form a circle, and no potential difference is formed at the head and tail, avoiding safety problems of the transformer when water quality problems occur; a small section of non-metallic pipe is set at the water inlet and outlet interface of the water cooling device, and the metal water cooling channel is transitioned to non-metallic material, and insulated by non-metallic material, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural diagram of the medium frequency transformer according to the first embodiment of the present invention.

[0031] Figure 2 It is a structural schematic diagram of the iron core assembly of the medium frequency transformer according to the first embodiment of the present invention.

[0032] Figure 3 1 is a schematic cross-sectional view of a medium-frequency transformer according to a first embodiment of the present invention (at a single core column).

[0033] Figure 4 It is a structural schematic diagram of the core water cooling device of the medium frequency transformer according to the first embodiment of the present invention.

[0034] Figure 5 It is a structural schematic diagram of the water-cooling assembly in the iron core of the medium-frequency transformer according to the first embodiment of the present invention.

[0035] Figure 6 It is a structural schematic diagram of the low-voltage winding of the medium-frequency transformer according to the first embodiment of the present invention.

[0036] Figure 7 It is a structural schematic diagram of the high-voltage winding of the medium-frequency transformer according to the first embodiment of the present invention.

[0037] Figure 8 It is a structural schematic diagram of a winding water cooling device of a medium frequency transformer according to the first embodiment of the present invention.

[0038] Figure 9 It is a structural schematic diagram of another winding water cooling device of the medium frequency transformer according to the first embodiment of the present invention.

[0039] In the figure, 01, core assembly; 02, winding assembly; 03, base;

[0040] 1. Coiled core; 11. Core column; 12. Upper yoke; 13. Lower yoke;

[0041] 2. Iron core water cooling device; 21. Iron core intermediate water cooling assembly; 211. U-shaped plate; 212. Straight plate; 213. Water pipe joint; 22. Iron core yoke water cooling assembly;

[0042] 3. Clamping assembly; 31. Upper clamping assembly; 32. Lower clamping assembly;

[0043] 4. Low-voltage winding; 41. Low-voltage coil; 42. Low-pressure water cooling device; 421. L-shaped structure; 43. Low-pressure glass mesh cloth; 44. High thermal conductivity epoxy resin;

[0044] 5. Insulation tube;

[0045] 6. High-voltage winding; 61. High-voltage coil; 611. Upper coil; 612. Lower coil; 62. High-pressure water cooling device; 621. Upper water cooling device; 622. Lower water cooling device; 63. High-voltage glass mesh cloth;

[0046] 71. Water cooling plate; 72. Curved tube; 73. Non-metallic tube;

[0047] 81. Pipe; 82. Metal sheet;

[0048] 91. Cooling water collecting pipe; 92. Cooling water inlet; 92. Cooling water outlet. DETAILED DESCRIPTION

[0049] The technical solutions of the embodiments of the present invention will be explained and described below. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation manner, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0050] Refer to Figures 1 to 9 , the high-power density and large-capacity dry-type water-cooled intermediate-frequency transformer of the embodiment of the present invention includes:

[0051] The iron core assembly, in a figure-eight shape, has two horizontal parts and two vertical parts;

[0052] The winding assembly has two groups and is respectively sleeved outside the two vertical parts of the iron core assembly;

[0053] Among them, the iron core assembly includes at least two wound cores and an iron core water-cooling device. The two wound cores are distributed along the thickness direction. The wound core includes an iron core column, an upper yoke and a lower yoke. The iron core water-cooling device includes an iron core intermediate water-cooling component located between the two wound cores and iron core yoke water-cooling components respectively located outside the upper yoke and the lower yoke of the wound core;

[0054] Among them, the winding assembly sequentially includes a concentric low-voltage winding, an insulating cylinder and a high-voltage winding from the inside to the outside. The low-voltage winding includes a low-voltage coil and a low-voltage water-cooling device. The high-voltage winding includes a high-voltage coil and a high-voltage water-cooling device.

[0055] The beneficial effects of the high-power density and large-capacity dry-type water-cooled intermediate-frequency transformer of the present invention are as follows: The iron core water-cooling device includes an iron core intermediate water-cooling component located between the two wound cores and iron core yoke water-cooling components respectively located outside the upper yoke and the lower yoke of the wound core. This layout of the iron core water-cooling device not only meets the cooling requirements of the iron core, especially the cooling requirements of the upper and lower yoke positions with higher temperature rise, solves the heat dissipation of the iron core, but also enables the cross-sectional area of the iron core column to be smaller, and the overall structure of the transformer is compact; The low-voltage winding includes a low-voltage coil and a low-voltage water-cooling device, and the high-voltage winding includes a high-voltage coil and a high-voltage water-cooling device, realizing reliable heat dissipation of the low-voltage coil and the high-voltage coil.

[0056] Embodiment 1

[0057] Refer to Figures 1 to 9 , the high-power density and large-capacity dry-type water-cooled intermediate-frequency transformer of the embodiment of the present invention includes:

[0058] The iron core assembly 01, in a figure-eight shape, has two horizontal parts and two vertical parts;

[0059] The winding assembly 02 has two groups and is respectively sleeved outside the two vertical parts of the iron core assembly 01;

[0060] The core assembly 01 includes at least two wound cores 1 and a core water-cooling device 2. The two wound cores 1 are distributed along the thickness direction. The wound core 1 includes a core column 11, an upper iron yoke 12, and a lower iron yoke 13. The core water-cooling device 2 includes an iron core intermediate water-cooling component 21 located between the two wound cores 1 and an iron core yoke water-cooling component 22 located outside the upper iron yoke 12 and the lower iron yoke 13 of the wound core 1.

[0061] Among them, the winding assembly 02 includes a concentric low-voltage winding 4, an insulating tube 5 and a high-voltage winding 6 from the inside to the outside. The low-voltage winding 4 includes a low-voltage coil 41 and a low-pressure water cooling device 42, and the high-voltage winding 6 includes a high-voltage coil 61 and a high-pressure water cooling device 62.

[0062] See also Figure 1 In this embodiment, the medium frequency transformer includes a base 03, an iron core assembly 01 and a winding assembly 02.

[0063] See also Figure 2 In this embodiment, the wound core 1 is of open overlap type, and the core intermediate water-cooling assembly 21 located between the two wound cores includes a U-shaped plate 211 and a straight plate 212 that are independent of each other, and the U-shaped plate 211 and the straight plate 212 form a ring.

[0064] In this embodiment, the core yoke water-cooling assembly 22 includes four water-cooling plates 71 located on both sides of the core assembly 01 in the thickness direction. The core assembly 01 also includes a clamping assembly 3, which fixes the core yoke water-cooling assembly 22, the core middle water-cooling assembly 21 and the two rolled cores 1.

[0065] In this embodiment, the clamping assembly 3 includes an upper clamping assembly 31 and a lower clamping assembly 32. The upper clamping assembly 31 and the lower clamping assembly 32 are the same. The upper clamping assembly 31 and the lower clamping assembly 32 both include two clamping frames, two screws and two nuts. The two ends of the screw pass through the two clamping frames, and the two nuts are tightened on the two ends of the screw.

[0066] In this embodiment, the wound core 1 is formed by stacking ultra-thin silicon steel sheets, or the wound core 1 is formed by winding an amorphous alloy strip or a nanocrystalline strip.

[0067] In this embodiment, each plate of the iron core water cooling device 2 is made of aluminum alloy as a base material, and a water flow channel is formed by groove friction welding or buried copper pipes.

[0068] In this embodiment, the insulation between the iron core water cooling device 2 and the wound iron core 1 is achieved by 0.2 mm insulating paper.

[0069] In this embodiment, see Figure 3 (Horizontal cross-section view), the center of the medium frequency transformer is concentrically provided with a wound core 1 and a water-cooling assembly 21 in the middle of the core, a low-voltage winding 4, an insulating cylinder 5 and a high-voltage winding 6 from the inside to the outside.

[0070] See also Figure 4 In this embodiment, the core water-cooling device 2 includes an intermediate core water-cooling assembly 21 located between the two wound cores 1 and core yoke water-cooling assemblies 22 located on the outside of the upper yoke 12 and the lower yoke 13 of the wound core 1. The intermediate core water-cooling assembly 21 includes a U-shaped plate 211 and a straight plate 212 that are independent of each other. The U-shaped plate 211 and the straight plate 212 form a ring. Independence indicates that each has a set of water pipe connectors 213. Core yoke water-cooling assemblies 22 are provided on both sides of the upper yoke 12 and the lower yoke 13 of the wound core 1. There are four sets of core yoke water-cooling assemblies 22 that are independently arranged.

[0071] See also Figure 5 In this embodiment, the U-shaped plate 211 of the core intermediate water-cooling assembly 21 has a water inlet and a water outlet. Due to the large area of ​​the U-shaped plate 211, two circuits are formed in the U-shaped plate 211, and the two circuits share a water inlet and a water outlet. The straight plate 212 of the core intermediate water-cooling assembly 21 has a water inlet and a water outlet, forming a single circuit in the straight plate 212 of the core intermediate water-cooling assembly 21.

[0072] See also Figure 6 In this embodiment, the low-voltage winding 4 also includes a glass mesh cloth and a high-thermal-conductivity epoxy resin 44. The low-pressure glass mesh cloth 43 is located on the inner and outer sides of the low-pressure water cooling device 42. The low-pressure glass mesh cloth 43 separates the low-pressure water cooling device 42 from the low-voltage coil 41 on the inner and outer sides. The low-voltage coil 41, the low-pressure water cooling device 42 and the low-pressure glass mesh cloth 43 are all encapsulated in the high-thermal-conductivity epoxy resin 44.

[0073] In this embodiment, the water inlet and outlet interfaces of the low-pressure water cooling device 42 are arranged at the lower part of the low-voltage winding 4 .

[0074] In this embodiment, the thickness of the low-voltage glass mesh cloth 43 satisfies the electric field strength ≤ 800 V / mm.

[0075] In this embodiment, the low-voltage coil 41 is wound with copper foil, and the thickness of the copper foil is ≤1.0mm. When copper foil with a thickness greater than 1mm is required, two copper foils are stacked and insulating paper is placed between the copper foils; alternatively, the low-voltage coil 41 is wound with multiple Litz wires in a layered flat winding manner, and each Litz wire is insulated with polyimide film or aramid paper.

[0076] See also Figure 7 In this embodiment, the high-voltage coil 61 includes an upper coil 611 and a lower coil 612 that are wound separately, and a high-thermal-conductivity epoxy resin 44 is filled between the upper coil 611 and the lower coil 612. The high-pressure water-cooling device 62 includes an upper water-cooling device 621 at the upper coil 611 and a lower water-cooling device 622 at the lower coil 612 that are independent of each other.

[0077] In this embodiment, the water inlet and outlet interfaces of the upper water cooling device 621 are located above the upper coil 611 , and the water inlet and outlet interfaces of the lower water cooling device 622 are located below the lower coil 612 .

[0078] In this embodiment, high-pressure glass mesh cloth 63 is provided on the inner and outer sides of the high-pressure water cooling device 62. The high-pressure glass mesh cloth 63 separates the high-pressure water cooling device 62 from the high-voltage coil 61 on the inner and outer sides. The high-voltage coil 61, the high-pressure water cooling device 62 and the high-pressure glass mesh cloth 63 are all located in the encapsulation of the high-thermal conductive epoxy resin 44; the thickness of the high-pressure glass mesh cloth 63 is 1.0-3.0 mm, which meets the electric field strength of ≤800 V / mm.

[0079] In this embodiment, the high-voltage coil 61 is wound with a rectangular copper electromagnetic wire, the thickness of the rectangular copper wire is ≤2.0 mm, and the width of the rectangular copper wire is ≤6.0 mm.

[0080] In this embodiment, the cooling water channels of the core water cooling device 2, the low-pressure water cooling device 42, and the high-pressure water cooling device 62 do not share both aluminum and copper. Fluid flowing in cooling water channels containing both copper and aluminum will generate conductive ions, which will cause electrochemical corrosion.

[0081] In this embodiment, the water inlet and outlet interfaces of the core water cooling device 2 , the low-pressure water cooling device 42 , and the high-pressure water cooling device 62 have insulating connecting portions.

[0082] See also Figure 8 In this embodiment, the low-pressure water cooling device 42 and / or the high-pressure water cooling device 62 includes at least two independent L-shaped structures 421 arranged in a ring. The L-shaped structures 421 include two vertically arranged water cooling plates 71 and an arc-shaped pipe 72 connecting the two water cooling plates 71. The water pipe joint 213 is connected to the L-shaped structures 421 through a non-metallic pipe 73. The L-shaped structures 421 are made of metal.

[0083] See also Figure 9 In this embodiment, the low-pressure water cooling device 42 and / or the high-pressure water cooling device 62 includes at least two independent L-shaped structures 421 arranged in a ring. The L-shaped structures 421 are formed by bending a pipe 81. The water pipe connector 213 is connected to the L-shaped structures 421 via a non-metallic pipe 73. Both the water pipe connector 213 and the L-shaped structures 421 are made of metal. A metal plate is welded to the L-shaped structures 421 formed by bending a pipe 81 to increase the heat absorption area of ​​the L-shaped structures 421.

[0084] See also Figure 1In this embodiment, the clamping assembly 3 is provided with several cooling water manifolds 91, each of which is provided with a cooling water inlet 92 or a cooling water outlet 92. The same winding assembly 02 shares a common cooling water manifold 91, cooling water inlet 92, and cooling water outlet 92. The core intermediate water cooling assembly 21 and the core yoke water cooling assembly 22 of the core water cooling device 2 can share a common water inlet and outlet, or they can be completely separate or partially shared. The entire core water cooling device 2 can also share a cooling water manifold 91 with one of the winding assemblies 02.

[0085] The beneficial effects of the high power density and large capacity dry-type water-cooled medium frequency transformer of the first embodiment of the present invention are as follows: the iron core water-cooling device 2 includes an iron core intermediate water-cooling assembly 21 located between the two wound iron cores 1 and an iron core yoke water-cooling assembly 22 located on the outside of the upper iron yoke 12 and the lower iron yoke 13 of the wound iron core 1. This layout of the iron core water-cooling device 2 not only meets the cooling requirements of the iron core, especially the cooling requirements of the upper and lower iron yokes 13 with higher temperature rise, but also solves the heat dissipation of the iron core. The cross-sectional area of ​​the iron core column can be smaller, and the overall structure of the transformer is compact; the low-voltage winding 4 includes a low-voltage coil 41 and a low-pressure water-cooling device 42, and the high-voltage winding 6 includes a high-voltage coil 61 and a high-pressure water-cooling device 62, so as to realize reliable heat dissipation of the low-voltage coil 41 and the high-voltage coil 61; the iron core intermediate water-cooling assembly 21 includes a U-shaped plate 211 and a straight plate 212, and the core assembly 01 can be opened to facilitate the winding assembly The assembly between the winding assembly 02 and the core assembly 01; the high-voltage coil 61 includes two parts, the upper coil 611 and the lower coil 612, which are wound separately, so that the interlayer voltage is low, the local discharge is small, the interlayer insulation thickness is reduced, and the upper and lower water outlet settings and insulation safety of the high-pressure water cooling device 62 are convenient, and it is also beneficial to reduce the volume of the high-voltage coil 61 and save costs; the low-pressure water cooling device 42 and the high-pressure water cooling device 62 of the winding assembly 02 both adopt two sets of independent L-shaped structures 421, which fit more closely with the coil. At the same time, the low-pressure water cooling device 42 and the high-pressure water cooling device 62 do not form a circle, and no potential difference is formed at the head and tail, avoiding safety problems of the transformer when water quality problems occur; a small section of non-metallic pipe 73 is set at the water inlet and outlet interface of the water cooling device, and the metal water cooling channel is transitioned to non-metallic material, and insulated by non-metallic material, which is safer.

[0086] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art will understand that the present invention includes, but is not limited to, the contents described in the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A high power density and large capacity dry-type water-cooled medium frequency transformer, characterized by: The high-power density and large-capacity dry-type water-cooled intermediate-frequency transformer includes: A core assembly (01) in a figure-eight shape, having two horizontal parts and two vertical parts; A winding assembly (02) with two groups, respectively sleeved outside the two vertical parts of the core assembly (01); Among them, the core assembly (01) includes at least two wound cores (1) and a core water-cooling device (2). The two wound cores (1) are distributed in the thickness direction. The wound core (1) includes a core column (11), an upper yoke (12) and a lower yoke (13). The core water-cooling device (2) includes a core intermediate water-cooling component (21) located between the two wound cores (1) and core yoke water-cooling components (22) respectively located outside the upper yoke (12) and the lower yoke (13) of the wound core (1); Among them, the winding assembly (02) sequentially includes a concentric low-voltage winding (4), an insulating cylinder (5) and a high-voltage winding (6) from inside to outside. The low-voltage winding (4) includes a low-voltage coil (41) and a low-voltage water-cooling device (42). The high-voltage winding (6) includes a high-voltage coil (61) and a high-voltage water-cooling device (62).

2. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 1, characterized in that: The core intermediate water-cooling component (21) includes an independent U-shaped plate (211) and a straight plate (212). The U-shaped plate (211) and the straight plate (212) enclose a ring.

3. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 2, characterized in that: The core yoke water-cooling component (22) includes four water-cooling plates (71) located on both sides in the thickness direction of the core assembly (01). The core assembly (01) further includes a clamping component (3). The clamping component (3) fixedly connects the core yoke water-cooling component (22), the core intermediate water-cooling component (21) and the two wound cores (1).

4. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 2, characterized in that: The wound core (1) is stacked by ultra-thin silicon steel sheets, or the wound core (1) is wound by amorphous alloy strips or nanocrystalline strips; and / or, Each plate of the core water-cooling device (2) uses aluminum alloy as the base material, and a water flow channel is formed by grooving friction welding or embedding copper tubes.

5. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 1, characterized in that: The low-voltage winding (4) further includes a glass fiber cloth and a high thermal conductivity epoxy resin (44). The low-voltage glass fiber cloth (43) is located on both the inside and outside of the low-voltage water-cooling device (42). The low-voltage glass fiber cloth (43) separates the low-voltage water-cooling device (42) from the low-voltage coils (41) on both sides. The low-voltage coils (41), the low-voltage water-cooling device (42) and the low-voltage glass fiber cloth (43) are all located in the encapsulation of the high thermal conductivity epoxy resin (44).

6. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 5, characterized in that: The water inlet and outlet interfaces of the low-voltage water-cooling device (42) are arranged at the lower part of the low-voltage winding (4); and / or, The thickness of the low-voltage glass fiber cloth (43) satisfies the electric field strength ≤ 800 V / mm; and / or, The low-voltage coil (41) is wound by copper foil. The thickness of the copper foil ≤ 1.0 mm. When copper foil > 1 mm is needed, two copper foils are wound in an overlapping manner, and insulating paper is padded between the copper foils; or, the low-voltage coil (41) is wound by multiple Litz wires in a layer winding manner, and each Litz wire uses polyimide film or aramid paper as insulation on the outside.

7. A high power density, large capacity dry-type water-cooled medium frequency transformer according to any one of claims 1 to 6, characterized in that: The high-voltage coil (61) includes an upper coil (611) and a lower coil (612) that are wound separately, and a high-thermal-conductivity epoxy resin (44) is filled between the upper coil (611) and the lower coil (612). The high-voltage water cooling device (62) includes an upper water cooling device (621) at the upper coil (611) and a lower water cooling device (622) at the lower coil (612) that are independent of each other.

8. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 7, characterized in that: The water inlet and outlet interfaces of the upper water cooling device (621) are located above the upper coil (611), and the water inlet and outlet interfaces of the lower water cooling device (622) are located below the lower coil (612); and / or, High-pressure glass mesh cloths (63) are provided on both inner and outer sides of the high-pressure water cooling device (62), and the high-pressure glass mesh cloths (63) separate the high-pressure water cooling device (62) from the high-pressure coils (61) on both inner and outer sides. The high-pressure coils (61), the high-pressure water cooling device (62) and the high-pressure glass mesh cloths (63) are all located in an encapsulation of a high-thermal-conductivity epoxy resin (44); the thickness of the high-pressure glass mesh cloths (63) is 1.0-3.0 mm, satisfying an electric field strength of ≤800 V / mm; and / or, The high voltage coil (61) is wound with a flat copper electromagnetic wire, the thickness of the flat copper wire is ≤2.0 mm, and the width of the flat copper wire is ≤6.0 mm.

9. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 1, characterized in that: The low-pressure water cooling device (42) and / or the high-pressure water cooling device (62) at least includes two independent L-shaped structures (421) formed in a ring shape, wherein the L-shaped structure (421) is formed by bending a pipe (81), or the L-shaped structure (421) includes two vertically distributed water cooling plates (71) and an arc-shaped pipe (72) connecting the two water cooling plates (71).

10. The high power density and large capacity dry-type water-cooled medium frequency transformer according to claim 1, characterized in that: The cooling water channels of the iron core water cooling device (2), the low-pressure water cooling device (42) and the high-pressure water cooling device (62) do not share aluminum and copper at the same time; and / or, The water inlet and outlet interfaces of the iron core water cooling device (2), the low-pressure water cooling device (42) and the high-pressure water cooling device (62) have insulating connecting parts.

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